Throttle valve opening



FIG. 1 is a plan view of a throttle valve opening, showing the claimed design.

FIG. 2 is a first perspective view of the throttle valve opening of FIG. 1; and,

FIG. 3 is a second perspective view of the throttle valve opening of FIG. 1.

The broken lines used in the figures are for illustrative purposes only and form no part of the claimed design. 

We claim the ornamental design for a throttle valve opening, as shown and described. 